Effect of nitrogen fertilizers on some biological aspects of the cotton aphid, Aphis gossypii glover infesting okra seedlings under semi- field conditions [electronic resource].

Includes references.

The effect of nitrogen fertilization at different rates on some biological aspects of the cotton aphid, Aphis gossypii Glover infesting okra seedlings was studied under semi-field conditions during the two successive seasons of 2005 and 2006. Okra seedlings were fertilized with three chemical nitrogen fertilizers namely; ammonium sulphate, ammonium nitrate and urea using four different rates of application; recommended rate (80 kgN/fad.), double recommended rate, half recommended rate and quarter recommended rate. Data revealed that nymphal period, adult longevity and generation period of the aphid were prolonged significantly as influenced by the tested fertilizers. Nymphal periods were averaged 8.02, 8.28 and 8.34 days for the above-mentioned fertilizers, respectively, comparing with 5.62 days for the control treatment. The averages of adult longevity were 15.78, 15.69 and 15.84 days for the tested fertilizers, successively, comparing with 12.87 days for the control. Also, generation periods were also prolonged and valued 23.80, 23.97 and 24.18 days, for the above-mentioned fertilizers, respectively, as compared with 18.49 days for the control treament.

Summary in Arabic.

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